<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        section{
            width: 80%;
            height: 200px;
            background-color: white;
            display: flex;
            margin: 0 auto;
        }
        div{
            height: 100%;
            /* 这样每个div都占一份, 那么就每个人1/3, */
            flex: 1;
            background-color: pink;
        }
    </style>
</head>
<body>
    <section>
        <div>1</div>
        <div>2</div>
        <div>3</div>
    </section>
</body>
</html>